Method for washing coal and concentrating ores and minerals



T. M. CHANCE.

METHOD FOR WASHING COAL AND CONCENTRATING O-REQ AND MINERALS. APPLICATION FILED AUG.27, 1917.

1,392,400, Patented 00a 4, 1921.

I 2o /1 z; {a 2 W/TNESSES: INVENTOR W JAM 2.14am

UNITED STATES PATENT QF-FICE.

un'rnon ron wAsnrNe COAL ToraZZ whom it may concern ;Be itknown that I, THOMAS M, CHANGE, acitizen of the United States, residin'g'at Philadelphimin. the State of Pennsylvania, have invented certain new and useful Improvements inlxiethods for Washing Coal and Concentrating Ores and Minerals,

' whereof thefollowing is a specification.

My invention relates to improvements adapted to be used in operating the method of washing coal and concentrating ores disclosed by me in United States Patent 1,224,- 138 dated May 1, 1917, wherein a fluid mass of relativelyv high specific gravity, consisting of a mixture of liquid and comminuted insoluble material. heavier than the liquid and maintained in a fluidic condition by agitation, is used to separate materials of spe cific gravity relatively greater than said fluid mass from those of specific gravity equalto or relatively less than said fluid mass. In the practice of the invention described in said patent the separation. of several substances of difi'erent'specific gravities can-be accomplished 'by introducing the materialfloated'or sunk in one such fluid mass into a second fluid mass of higher or lower specific gravity, and if necessary into a third fluid mass and so onuntil the desired separation is efiected. My present inven- .tion consists in improvements whereby two or more fluid masses of difi'erent specific .graviti'es may be simultaneously employed in a common separating tank or receptacle for? such differential separation, the fluid mass of lower specific gravity being superimposed upon that'of higher specific gravity. Aiu'rther object of my invention relates to the employment vof such plural fluid masses in conjunction with a body of liquid of less specific gravity superimposed thereon. I

For simplicity the word wateriwill be used to-nean any liquid suitable for the purpose, and the word sand will be used to mean any granular insoluble material heavier than'the liquid and which will sink readily in said-liquid unless maintained suspended in said liquid by agitation.

I have found,'as disclosed in said patent, that agitation suitable for the purpose of fmaintalning the fluid mass can be produced either by energy applied mechanically,

(as by stirring arms, etc.) or by energysupplied by liquid under pressure. Itis evident Specification of Letters Patent.

AND CONCENTRAIIIIG OBES. AND

Patented Oct. 4,, 1921.

Application filed August 27, 1917. Serial N jo. 188,431.

tnat the energy theoretically required will be the same whether applied mechanically or by the introduction of liquid under pressure, but it is also evident that they energy in which it is applied, because much of the energy applied to effect agitation may be expended in friction and thus become dissipated as heat and have no useful effect in producing the agitation necessary to overcome, ;or to neutralize, the tendency of the individual particles of the solid matter tesettle by gravity.

It is evident that if I use fixed quantities of sand and water as the constituents of such a fluid mass, and mechanically apply agitation suflicient to keep the sandand wa- 'ter thoroughly mixed, the fluid. mass will have a definite and fiired specific gravity which is fixed by the. relative proportions of sand and water used; but'if agitation is applied to such mixture by the introduction of liquid under pressure,-e-hereinafter for convenience called hydraulic water,-the predetermined relations between the proportions of sand and water are disturbed or destroyed, and the control 'of the specific gravity and volume of the fluid mass to conform tov "any predetermined reqilired conditions must be accomplished by regulating'theuse of the hydraulic water tesiinhquantity and to such head or pressure as wil'l'- -secure the desired result,

The most simple and obvious way'in which to apply hydraulic water to effect agitation isito" introduce it from below (as through av perforate bottonfl'ras an upwardly rising current, oras a series of isolated jets. In A effecting agitation in this way, if a given 'quantityofsand be used, a fluid mass of definite specific gravity is formed and maintained by a definite volume of hydraulic water introduced perunit of time under a definite head or pressure :If the volume of hydraulic water be increased the grains of sand are more forcibl agitated and are forced farther apart an the specific gravity of the fluid mass is correspondingly de-' creased and the volume of the fluid mass is correspondingly increased,-and vise versa. I have found that agitation giving similar results can be produced by 'ets of hydraulic water introduced in any desired direction and at any desired height above the bottom of the fluid mass. Such jets may be made to issue from orifices in pipes located in the body of the fluid mass and may be discharged in a vertically downward direction, or at any desired angle, and may be made to produce the agitation necessary to maintain the fluid mass at the desired specific gravity and of the desired volume. When agitation is effected by energy partly applied mechanically and partly applied by means of hydraulic water, the quantity of hydraulic water required to maintain the fluid mass at a certain specific gravity and volume steadily diminishes as the mechanical agitation is increased. I

By providing means for closely adjusting the specific gravity of such fluid masses and for maintaining the specific gravity at the desired density, I find it is possible to superimpose upon a fluid mass of high specific gravity another similar fluid mass of less specific gravity, or to superimpose a fluid mass of low specific gravity upon another similar fluid mass of higher specific gravity. If desired, I may maintain a reasonably distinct line of demarcation between the fluid masses of different specific gravities, or I may permit the differences in specific gravities to merge gradually from .that of the upper fluid mass to that of the lower fluid mass. It thus becomes possible to create and maintain two or more distinct zones, in each of which a fluid mass can be made to maintain (between certain limits) such specific gravity as may be desired, zones of lighter specific gravity being of course above 'those of heavier specific gravity. It is evident that the creation and maintenance of Such a series of zones of different specific gravities will permit the separation of three or-more kinds of material having different specific gravities, similar to the successive treatment of such materials by separate fluid masses of different specific gravities above referred to in said Patent 1,224,138.

We ma thus effect the separation of light-an hence low ash-coal, valuable for coking, from the heavier and higher ash coal, and this latter in turn from the bone and laminated coal (ver impure coal and interstratified coal and sl ate). this bone or laminated coal being in turn separated from waste such as fire-clay, slate, shale, pyrite, etc., each of these several classes of material, except the waste, being separated by floating in a fluid mass through which it is not heavy enough to sink, and from which bysuitable a liances it can separately be removed. ren or worthless gangue or rock, from gangue containing ore (middlings, to be recrushed to free the ore) and the separation of middlings from clean or highgrade ore, and the separation of the constituents of complex ores consisting of gangue and two or more minerals of dife separation of bar-- ferent specific accomplished.

If means be provided for the accurate and definite control of the degree of agitation, that is, if the agitation be uniform and constant, so that a fluid mass of definite and practically constant specific gravity and volume is produced and maintained, it is possible tosuperimpose upon such fluid mass a body of liquid of less specific gravity than that of said fluid mass, and the use of a body of liquid thus superimposed upon a single fluid mass employed in making simple twopart separations is described in a co-pending application for patent filed by me, of even date herewith, Serial Number 188,430, for method and apparatus for washing coal and concentrating ores, in which said application I have broadly claimed the combination of a body of liquid superimposed upon a fluid mass of the described type; I therefore herein have limited myclaims to combinations consisting of compound fluid masses of the types herein described, with or Without a body of liquid superimposed thereon. Such a body of water (liquid) may likewise be superimposed upon a compound fluid mass of the type described herein and may be used to wash off from the separated materials that are removed from said fluid mass, particles of sand mixed therewith. This superincumbent water may thus be used in the separating tankas wash water, the sand that is washed from the separated materials immediately sinking through' the water to become reincorporated as a part of the fluid mass.

This superincumbent water may also be advantageously used to remove from the materials to be washed or concentrated, prior to their introduction into the fluid mass for separation, substances such as mud, slimes, dirt and the like, as well as materials lighter than Water such as wood, rope, yarn, cotton, cloth, burlap, paper, etc., that may be mixed with the ore, coal or other material that is to be washed or concentrated gravities may be likewise thus by introduction into the said fluid mass;

pound fluid mass consisting of two zones 'of different specific gravities with a body of liquid superimposed upon said fluid mass. The drawing Fig. II shows an enlarged cross-section of one of the agitating elements used in the o eration of the device shown, in Fig. I. ike numbers indicate mass.

. %yin uid; the lighter or uppermost like parts both of the drawings. Fig.

III is an end view showing the dewatering screens 7 and 7 v In the drawing Fig. I, 1 is a receptacle, conventionally shown as a-tank, adapted to contain a compound fluid mass, consisting of two zones of an agitated mixture of liquid and comminuted insoluble solid matter heavier than said liquid, and a-body of liquid superimposed upon said-compound fluid The upper surface of said body of liquid is indicated by the dot and dash line A-A, the upper surface of the low specific gravity zone of said compound fluid mass by the line BB and that of the high specific gravity zone of said compound fluid mass by the line C-Q. The water occuthe space between lines A-A and is indicated by the conventional broken parallel lines used to indicate liqfluid mass occupying the space between lines C-C is diagrammatically indicated b parallel lines representing liquid with the addition of stippling to indicate the grains or particles of the solid constituent ofsaid fluid mass theheavier or lower fluidmass occupying the space below the line CC is indicated in the same manner except that thestippling shows the presence of a larger er-j centage of the solid constituent of said I uid mass, than is shown in the lighter fluid masssuperimposed thereon. The tank 1 is 'provided withv flight conveyer 2 for the removal'of the material floated by the upper zone of the-compound fluid mass, conveyer 3 and elevator 4 for the removal of material of intermediate specific gravity sinkin in zone =B B and floating in zones 0- and conveyer 5 and elevator 6 for the removal of the heavy material that sinks in .both zones of the compound fluid mass. A

screen 7 is provided for the removal of parts of the fluid mass and'water adhering to the light material removed by conveyer 2, said screen 7 being provided with boot 8 and conduit 9 for the collection of the comminuted solid material andwater removed by said screen. It will be understood that the elevators 4 and 6 are likewise provided with dewatering screens similar to the screen 7 shown in the end elevation, Fi III, and indicatedby the numbers 7 'and It will further be understood that the portion of the fluid ma'ssandwater reclaimed by said dewatering screens may be returned to. the tank 1 by suitable elevating devices. chute 10 1s provided for flight conveyer 2 and this chute may be advantageously provided with perforations as shown, to per mit the reclaiming of'a considerable portion of the comminuted solid material and waterwithout remo'valfrom the tank 1.

- Pipes 11 provided with perforations 12 and connected through manifold13 and cut- -B a the fluid mass, while pipes 16, provided with perforations 17, and connected through manifold 18 and cut-off valve 19 to said hydraulic line 15 permit the introduction of hydraulic water for theagitation of the lower zone C-C of the compound fluid mass, it being understood that the hydraulic line 15 is connected to a suitable source of supply of liquid under pressure.

A feeding device is diagrammatically shown b 21, are s own for the introduction of water under pressure to the bearings of the conveyer. shafts that operate in the fluid mass vto prevent'cutting by the same. An overflow for excess liquid is shown at 22 and means for applying wash water to remove portions of the fluidmass adhering to the material passing over the screens 7 are shown by the spray pipes 23, it being understood that said pipes are connected to a suitable source of liquid supply. It will of course be understood that the dewatering screens. provided for elevators 4 and 6 may 'lar to those just described.

Fig. I'is as follows: w

' The tank being filled to the proper level with a mixture of comminuted insoluble solid matter and liquid, agitation thereof is effected by the hydraulic water, issuing through apertures 12 and 16 of pipes 11 and 17 and under the control of valves 14 and 19 "respectively. Difli'erential agitation of the comminuted solid material and liquid is thus effected and a compoundfluid mass is thereby produced. The specific gravity of the upper zone' BB- of this compound fluid mass will be dependent upon the agitation produced by the jets -of hydraulic water issuing from holes 12 in pipes 11 and also to a certain extent-by agitation effected by the jets from the lower hydraulic water pipes 16, while that of the'lower zones CC of the. compoundfiuid mass will be dependent upon the agitation produced by the jets from the hydraulic water ipe 16, these jets issuing from holes 17. tation is of'course produced by the operation of conveyers. 3 and 5- and bucket elevators 4 and 6. The'agitation produced by the conveyers 3 and 5 willbf course depend upon" the wings of e screw and the speed at which they are operated. If desired theymaybe especially designed, not only to effect transfer of the materials but also to act as mechanical'agitators, and are intended to be The operatlon of the apparatus shown in ome further agipitch and size of the blades or t the numeral 20 and pipes, as at be likewise provided with spray pipes simidiagrammatically illustrative'of such, and

my invention. They can of course be operat'ed at any desired speed, can be made large or small, and operated at any desired angle from the horizontal.

If'a mixture of sand and water be employed for producing thercompound fluid mass-in the tank 1 and if a mixture of coal,

bony coal and slatebe introduced into this compound fluid mass, by feeding device 20,the upper zone B-B of said fluid mass being' maintained at about 1.45 specific gravity and the lower zone at about 1.70 specific gravity,the light pure coal will float in'the upper portion of the zone B-B and will be removed therefrom by the flight conveyer 2, being transported up the chute 10 an'd'through the body of clear water resting upon the compound fluid mass, the top line of which indicated by the dot and dash line A-A. This transportation of the washed coal through the body of liquid AA will of course result in washing oil a considerable portion of any comminuted solid material composing the fluid mass that may be mixed with the washed coal, this solid material returning to the fluid mass in tank -1 through the apertures of screen 10.

The remaining portion of the comminuted material, together with the entrained water, will be removed largel .by passage over dewatering screen 7 an may be returned by conduit 9 to the tank 1.

The heavier bony coal will sink through this upper zone B-B but will float in the upper portion of the zone CC of the com- 7 pound fluid mass and will be removed therefrom by screw conveyer and bucket elevator 4, while the heavy slate, pyrite and other refuse sinking through the lower zone C-C of the fluid mass will be caught by conveyer 5 and delivered to bucket elevator 6, being thus removed from the fluid mass in tank 1. It will of course be understood that conveyers 3 and 5 may. be driven'by bucket elevators 4 and 6 as shown, or that separate drives may be provided.

mass, in the case specifically referred to the densities are suitable for some, grades of soft coal, and it will of course be understood that thespecific gravity necessary for use.

with other materials, such as metalliferous ores, may be quite different from those noted.

The elevators 4 and 6, for removi the separatedimaterials from the'body d the fluid mass, are diagrammatically shown as bucket elevators, but it will be understood that any desired form of elevating device may be used for erfo-rming the functionsof these elements of the apparatus. If bucket elevators or flight conveyors are used for this purpose, the buckets or flights would preferably be of the perforated type employed in dewatering elevators and conveyors. Similarly, flight conveyer 2 may be replaced by any desired form of elevating device.

Fig. II is an enlarged cross-section of one of the hydraulic water pipes 11 and shows the method of providing apertures 12 for producing the hydraulic jets" that are used in agltating the com und fluid mass. It will of course be un erstood that the construction of pipes 16 is similar to that of pipes 11 and that the jet apertures 12 and I 17 may be formed to play in any desired direction, it not being essential to follow the. particular construction shown in this Fig. II.

It will also be clear that the arrangement of hydraulic water pipes 11 and 16, together with jets 12 and 17, need not always be used in the operation of my invention and that many other means toeffect agitation, as exemplified by Patent No. 1,224,138 above quoted, may be readily employed by any skilled in the art.

It will be understood that in constructing apparatus for the use of my invention I do not confine myself to the particular form or style used in the drawings to illustrate the application .of my method, as it is evident that in constructing such apparatus a great variety of appliances in common use for handling solids and for handling liquids may advantageously be'employed for like purposes in carrying out my invention.

In U. S. Patent 1,224,138, a number of modifications of apparatus for employing mechanical, hydraulic and pneumatic agitation are shown and described, together with various appliances for'feeding the materials to be separated into the fluid mass, removing the-separated materials from said; fluid mass and recovering the portions of said fluid removal. It will be understood that such modifications as may be applicable to my present invention may be employed by any skilled in the art, the apparatus necessary mass adhering to said materials after such to the employment of my invention generally comprisingthe following elements a receptacle adapted to contain a compound fluid mass, said mass consisting of two or more. zones of different specific gravity of an agitated mixture of comminuted solid materialand liquid, a body of liquid superim osed upon said fluid mass, means for di erentially a 'tating said fluid mass, means for intro separated therein, and means for the removal of the separated materials therefrom ucing the materials to be after separation has been accomplished. It will of course be understood that if mechanical methods of agitation are employed, devices similar to those described and shown in Patent'No. 1,224,138 may be substituted for erals of lower gravity than those that sink Such a clifl'erentiation.

in the lowest zone. might be made, for example, inv separating zinc blend and galena, the galena sinking to. the bottom of the fluid mass and the blend at an intermediate point.- In cases of this kind comminuted .middlings or concentrates themselves maybe employed as a comminuted solid material composing the:

fluid .mass, and such use of thesematerials is referred to in the-above patent. A further advantageof 'the use of such materials for producing the fluidfmass is found in the fact that I; may employ "comminuted material of high, specific gravity, such as galen af and the like, to produce-the lower zone of thecompound fluid mass and lighter comminuted :material, such as magnetite,

zinc blend, galena middlings etc. for producing the upper zones. n It will be clear that under such conditions the specific gravity of the various zones will depend on both the degree of agitation in any particular zone andalso upon the specific gravity of the comminuted solid material used in that particular zone for the production of the compound fluid mass. It will be' necessary under such conditions to carefully proportion the agitation to the specific gravity of the comminuted materials forming each particular zone in the compound fluid mass so that the desired specific gravity of each zone of said fluid mass may be maintained. Itwill be, understood that. differences in size. of comminuted material of any certain specific gravity used to form the fluid mass may likewiseafi'ect the specific gravity ofthe various zones composing the" fiuid mass and that this deflerencein size will also require proper proportioning of the agitation to attain the desired specific gravities in said different zones.

Under some conditions it may be advantageous to apply hydraulic'water for agitation in the vicinity of the elevating devices used for removing the separated materials, such agitation being useful in attaining and maintaining the fiuidic properties of those portions of the fluid mass surrounding said tank and the suporincumb elevating devices e. 9., when the apparatus is to be started and the mixture used for forming said fluid mass is at rest,and

such additional agitation ma? be providedby the introduction of hydraulic agitating devices similar to those described for the agitation of the main fluid mass in the drawing Fig. I.

While in the embodiment of my invention shown in the drawing Fig. I, a body of liquid is-provided, superimposed upon the compound-fluid mass contained in the separating tank 1, it-will be understood that I do not limit myself'to the employment of such a body of liquid and that in'the operation of myinvention this body of liquid may often be omitted, such omissionibeing entirely within the scope of my invention. For example, if the discharge of the separated material of lowest specific gravity be her similar to that shown in someforms of apparatus illustrated "in Patent-1,224,138 above referred 9,the'oompound 'fl'uid mass alone need be contained in the separating may be dispensed with.

m Q YOf liquid It .will of course be understood that'the location ofthe top surface of the zones'of different specific "gravity of the fluid mass,

indicated by the dot and dash lines B=-B and C C,, and also the top of the body of liquid, vindicated by the dot and dash line A-A, in Fig. I, may be varied to meet the requirements of the particular separation to be made and are not to beconsidered as fixed at the points shown by saiddrawing.

1 By the term fluid mass as used-in the claims hereof I mean to include any agitated 'liquidand particles of solid matter heavier I mixture of commin'uted solids and liquid .which when properlyagitated will approach theproperties and fluidity of a true'liquid than the liquidand maintained by agitation .in zones of relatively difierent specific gravities; in permitting the materials ofrelatively low specific gravity to rise to and float in the upper portion of the low density zones of of relatively higherspecific'gravity to rise.

to and floatin theupper portion of the high said fluid mass; in permitting the materials to sink to the lower portion of the highest density zone;.ii1 separately removing the materials thus separated from said compound fluid mass and m transporting the 85" effected by the overflow of the-upper zone of '7 the compound fluid mass itself,'in a manmaterials of low specific gravity'thus removed through a body of liquid superimposed upon said compound fluid mass; and thereby removing some of the comminuted solid matter of said mass mixed with said separated materials.

2. A method of separating materials by means of differences in their specific gravities which consists 'in immerslng said materials in a compound fluid mass composed of liquid and particles of solid matter heavier than the liquid and maintained by agitation in zones of relatively different specific gravities; in permitting the materials of relatively low specific gravity to rise to and float in the upper portion of the low-densityrzones of said fluid mass; in permitting the materials of' relatively higher specific gravity to rise to and float in the upper ortion of the high density zonesof said uid mass; in

permitting the materials of highest specific gravity to sink to the lower portionoof the ighest density zone; in separately removing the materials thus separated from said fluid mass and in transporting the materials thus removed through a body of liquid superim osed upon said compound fluid mass,

and t ereby removing some of the comminuted solid matter of said mass mixed with said separated materials.

3. A method of washing coal which consists in feeding said coal into a compound fluid of sand and water and maintained by agita-- mass composed of an agitated mixture of sand and water andmaintained by agitation I in zones of relatively different specific gravities spec i c gravity to rise to and float in the upper portion of the low density zone of said fluld mass; permitting the coal, "bony coal and impurities of relatively higher specific gravity to rise toand float in the upper ortion of the high, density zone of said uid mass; permitting the impurities of.highestspecific gravity to sink to the lower portion of said fluid massand separately removing the coal andimpurities thus separated from said compound fluid mass.

4. A method of washing coal which consists in feeding said coal into a compound fluid mass. composed of an agitated mixture tion-in zones of relatively difl'erent specific gravities; permitting the coal of relatively low specific gravity to rise to and float in the upper portion of the low density zone of said fluid mass; permitting the coal, bonycoal and impurities of relatively higher specific gravity to rise to and float-in the- .-upper portion of the high density zoneofj ermitting the coal of relatively low said fluid mass; permitting the impurities of highest specific gravity to sink to the lower portion of said 'fluid mass; separately removing the coal and impurities thus separated from said compound fluid mass and in transporting the coal thus removed through a body of liquid superimposed upon said fluid mass, and thereby removing some of the comminuted solid matter of said mass tively low speclfic gravity to rise to and float in the upper portion of the "low den-g sity zone of said fluid mass; permitting the coal and impurities of relatively higher specific gravity to rise to and float in the upper portion of the high density zone of said fluid mass; permitting the impurities of highest specific gravity to sink to the lower portion of said fluid mass; separately'removin the coal and impurities thus sepa-.

rated rom said compound fluid mass and in transporting the coal and impurities thus removed through a body of liquid superim posed upon said fluid mass, and thereby removing some of the comminuted solid matter of said mass mixed with said separated coal and impurities.

6. A method of washing coal which consists in feeding saidcoal into a compound fluid mass composed of liquid and particles of solid matter/of specific gravity greater than that of the liquid and than that of the coal; maintaining said com ound fluid mass in superposed zones of gravities; causing the coal of relatively low speclfic gravity to rise to and float in the upper portion of the low-density zone of said fluid mass; causing the coal, bony coal and impurities of relatively higher specific gravity to rise to and float in the upper portion of the high density zone ofsaid fluid mass causing the impurities of higher specific gravlty to sink to the lowerportion of said uld mass and separately removing the coal and impurities thus separated from said compound fluid. mass.

In testimony whereof I have hereunto signed my name at Philadelphia, Pennsylvanla, this24th da of August,1917.

TH OMAS M. CHANGE.

Witnesses:

E. R.BARNARD, J H. QUINN. 

